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arXiv · 2301.02653

Single electron-spin-resonance detection by microwave photon counting

Zhiren Wang·Léo Balembois·Milos Rančić·Eric Billaud·Marianne Le Dantec·Alban Ferrier·Philippe Goldner·Sylvain Bertaina·Thierry Chanelière·Daniel Estève·Denis Vion·Patrice Bertet·Emmanuel Flurin
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Abstract

Electron spin resonance (ESR) spectroscopy is the method of choice for characterizing paramagnetic impurities, with applications ranging from chemistry to quantum computing, but it gives access only to ensemble-averaged quantities due to its limited signal-to-noise ratio. Single-electron-spin sensitivity has however been reached using spin-dependent photoluminescence, transport measurements, and scanning-probe techniques. These methods are system-specific or sensitive only in a small detection volume, so that practical single spin detection remains an open challenge. Here, we demonstrate single electron magnetic resonance by spin fluorescence detection, using a microwave photon counter at cryogenic temperatures. We detect individual paramagnetic erbium ions in a scheelite crystal coupled to a high-quality factor planar superconducting resonator to enhance their radiative decay rate, with a signal-to-noise ratio of 1.9 in one second integration time. The fluorescence signal shows anti-bunching, proving that it comes from individual emitters. Coherence times up to 3 ms are measured, limited by the spin radiative lifetime. The method has the potential to apply to arbitrary paramagnetic species with long enough non-radiative relaxation time, and allows single-spin detection in a volume as large as the resonator magnetic mode volume ( 10 um^3 in the present experiment), orders of magnitude larger than other single-spin detection techniques. As such, it may find applications in magnetic resonance and quantum computing.

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Zhiren Wang, Léo Balembois, Milos Rančić, Eric Billaud, Marianne Le Dantec, Alban Ferrier, Philippe Goldner, Sylvain Bertaina, Thierry Chanelière, Daniel Estève, Denis Vion, Patrice Bertet, Emmanuel Flurin. 2023-01-06. Single electron-spin-resonance detection by microwave photon counting. https://doi.org/10.1038/s41586-023-06097-2

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